This predicate is similar to ST_Within except for one subtle difference. The ST_Within predicate
requires that one or more interior points of the geometry-expression lie in the interior of geo2.
For ST_CoveredBy(), the method returns 1 if no point of the geometry-expression lies outside of
geo2, regardless of whether interior points of
the two geometries intersect.
ST_CoveredBy can be used with geometries in round-Earth spatial reference
systems.

Note

If the geometry-expression contains circular strings, then these are interpolated to line strings.

The following example tests if a line is covered by a polygon. The line is
completely covered by the polygon so the example returns 1.
If ST_Within was used in place of ST_CoveredBy,
ST_Within would return 0.

The following example lists the ShapeIDs where the given point is
within the Shape geometry. This example returns the result 3,5,6.
Note that ShapeID 6 is listed even though the point intersects
that row's Shape polygon only at the polygon's boundary.